Surgical electric welding apparatus

ABSTRACT

A surgical electric welding apparatus for interconnecting bone implantations, said apparatus comprising a transformer whose primary winding may be connected to an electric energy source, two welding electrodes connected to the terminals of the secondary winding of the transformer by means of a flexible cable and held in a handle, an electronic unit for controlling the closure of the feeding circuit of said primary winding and safety means for preventing said circuit from being improperly closed.

United States Patent inventor Jacques Robert Weber! Montrouge, France Appl. No. 805.213

Filed Mar. 7, 1969 Patented May 18, 1971 Assignee Commksariat a IEnergie Atomique Paris, France Priority Dec. 31, 1968 France PV182649 SURGICAL ELECTRIC WELDING APPARATUS 12 Claims, 2 Drawing Figs.

US. Cl 219/114 Int. Cl 823k 11/26 Field of Search 219/114, 116,108, 78, 86

[56] References Cited UNITED STATES PATENTS 3,234.354 2/1966 Penberg 219/108X 3,330,993 7/1967 Ulrich 219/1 14X Primary Examiner-Bernard A. Gilheany Assistant E.raminer-Roy N. Envall. Jr. Attorney-Craig, Antonelli, Stewart and Hill ABSTRACT: A surgical electric welding apparatus for interconnecting bone implantations, said apparatus comprising a transformer whose primary winding may be connected to'an electric energy source, two welding electrodes connected to the terminals of the secondary winding of the transformer by means of a flexible cable and held in a handle, an electronic unit for controlling the closure of the feeding circuit of said primary winding and safety means for preventing said circuit from being improperly closed.

Patented M 18, 1971 3,578,941

2 Sheets-Sheet 2 INVENTOR JRCOUE6 IJE BERT BY 6L7.

ATTOR NEYS SURGICAL ELECTRIC WELDING APPARATUS The present invention relates to a surgical electric welding apparatus and, more particularly, to an apparatus for performing welded interconnection of bone implantations, and especially, of temporary or definitive implantations made for maintaining fractures andof implantations used in dentistry for allowing the artificial restoration of missing teeth or the healing of floating teeth.

Bone implantations, generally said -implantation-needles are cylindrical tantalum rods having a diameter of 1.2 to 1.8 mm. and are inserted into the bone by rotative perforation. Except in quite exceptional cases, more than one needle are always used; their number, their length and their direction depend on the charges that have to be dispersed within the bone. Singly considered, every needle represents only a small mechanical value and it is the assembly of needles that has the mechanical properties necessary for resisting the forces created, for instance, by the masticatory function. It can be therefore easily understood that the success of such an operation depends, in a great measure, on the interconnection of the implantation. As a matter of fact, the best implantation will not succeed if the connection of the needles is not sufficient or is failing in time. Moreover, the execution of the prosthesis, which is the final object of the implantation, is greatly affected by the mode of connection of the needles. In a general manner, the best mode of connection is the one providing to the most rigid connection and making use of the smallest quantity of added material.

A number of methods have been tested up to now for performing said interconnection, in particular, by embedding the heads of the needles with an autopolymerizable acrylic resin, by mounting on the heads a premanufactured connecting member made of a material known by the name of Teflon, by screwing a metallic member, by casting an alloy having a low fusion point, but none of these methods has been satisfactory, particularly account of the volume added on the needle heads, of the small mechanical resistance of the connection and of the heat heating created by the operation.

A first object of the present invention is the provision of an apparatus which permits the welded interconnection of bone implantations.

Another object of the present invention is the provision of an apparatus which permits the interconnection of the implantations without any addition of metal, and therefore, witha substantially reduced amount of material.

Another object of the present invention is an apparatus for the interconnection of the implantations without the risk of I burning the patient.

Another object of the present invention is an apparatus for the interconnection of the implantations without any risk of electrical hazards to the patient.

The surgical electric welding apparatus according to the in vention, used for interconnecting bone implantations, is essentially characterized in that it comprises a transformer whose the primary winding can be connected to an electric energy source, two welding electrodes connected to the terminals of the secondary winding of said transformer by means of a flexible cable and held in a handle, an electronic unit for controlling the closure of the feeding circuit of said primary winding and safety means for preventing said circuit from being improperly closed.

The invention will be now described by way of a nonlimitative example with reference to the accompanying drawings in which:

FIG. 1 is the electronic diagram of and circuit of the welding apparatus according to the invention;

FIG. 2 is a view of said apparatus used for welding two dental implantations.

As shown in FIG. 1, the welding apparatus according to the invention comprises the following circuits;

a noise-suppressor l for the main voltage used as the energy source,

a stabilized voltage generator 2 fed by the circuit 1,

a control signal generator 3 fed by the generator 2,

a shaping gate 4 for the signals supplied by the generator 3,

two cascade connected Schmitts triggers 5 and 6,

a selector 7 allowing the use of either of the pulses of the first trigger 5 or the pulses of both the triggers for performing the weld,

a microswitch 8 for controlling the first trigger 5,

a safety circuit 9 for the control signal supplied by said microswitch,

an amplifier 10 for the signals supplied by the triggers,

a welding head 11,

. a control circuit 12 for feeding said head, controlled by the amplifier 10.

' The noise suppressor 1, surrounded by a shield 13 connected to ground, comprises two identical filters. The main voltage 220 v. is supplied to the input terminals 14 and 15 through two shielded cables 16 and 17 whose the shield is also connected to ground. The output terminals are indicated at 18 and 19. Every filter is made of an inductor 20 connected between an input terminal and an output terminal and whose the extremities are connected to ground through two capacitors 21 and 22.

The noise-free voltage appearing across the output terminals 18 and 19 is applied to the primary winding of a transformer 23 acting as the input component of the stabilized voltage generator 2. The latter is surrounded by a shield 24 connected to ground and it has four output terminals 25, 26, 27 and 28. The secondary winding of the transformer 23 has two output taps 29 and 30 and two tapping points 31 and 32. The end tap 29 is connected to the output terminal through a diode 33 and a resistor 34; the tapping point 31 is directly connected to ground and tapping point 32 is connected to the output terminal 27 through a diode 35 and a resistor 36; end tap is connected to the output terminal 28 through a resistor 37 and a potentiometer 38. The cathodes of the diodes 33 and are interconnected. The resistor 34 is connected to the conductor connected between the tapping point 31 and the output terminal 26, through a capacitor 39 from one of its terminals, and through a capacitor 40 in parallel with a Zener diode 41 from its other terminal. The resistor 36 is connected to the same conductor through a capacitor 42 from one its terminals and through two Zener diodes in series 43 and 44 from its other terminal. Outputs 26 and 28 are interconnected through a capacitor 45. In said conditions, voltages having the values 12, 0 and 20 v. appear at the output terminals 25, 26 and 27, respectively, and an AC voltage controlling the circuit 3 appears at the output terminal 28.

The circuit 3, which generates the signals applied to the triggers, is provided with four input terminals 46, 47,48 and 49 respectively connected to-the output terminals 25, 26, 27 and 28 of the circuit 2 and with four output terminals 50, 51, 52 and 53. The input terminals 46, 47 and 48 are connected to the output terminals 50, 51 and 52 through the conductors 54, 55 and 56, respectively. Said circuit comprises essentially two PNP transistors 57 and 58; the base of transistor 57 receives the AC signal issuing from the circuit 2 through a connecting capacitor 59; said-base is also connected to the conductor 55 through a resistor 60 and to'the conductor 54 through a resistor 61; the emitter of transistor 57 is connected, on one hand, to the conductor 54 through a resistor 62 and, on the other hand, to the emitter of the second transistor 58. The collector of the transistor 57 is connected to the conductor 55 through a resistor 63 and to the base of the second transistor 58 through a resistor 64. The collector of the transistor 58 is connected to the conductor 55 through a resistor 65 and to the output terminal 53 through a capacitor 66.

The signals appearing at the collectors of the transistors 57 and 58 of the generator have the represented shape 57 and 58'. The potentiometer 38 cooperating with the connecting capacitor 59 ensures the emission of the signals generated by said circuit at a predetermined time of every positive halfwave of the main voltage, with an adjustable given delay imposed to the voltage applied to the base of the transistor 57.

Said signals appearing at the terminal 53 are applied to the gate 4 that shapes them. Said gate has four input terminals 67,

68, 69 and 70 connected to its four output terminals 71, 72, 73 and 74 and it comprises essentially a resistor 75 and a diode 76 connected in parallel between the conductor connecting the terminals 67 and 71 and the conductor connecting the terminals 70 and 74. The shape of the signals supplied by said gate and appearing at its output terminal 74 is shown at 74'. Said signals are applied to the cascade connected triggers and 6.

The first trigger 5 has five input terminals 77, 78, 79, 80 and 81, the first four being respectively connected to the output terminals 71, 72, 73 and 74 of the gate 4, and the fifth 81, to the safety circuit 9, and five output terminals 82, 83, 84, 85 and 86. The input terminals 77, 78 and 79 are connected to the output terminals 82, 83 and 84 through the conductors 87, 88 and 89, respectively. The output terminals 83 and 85 are interconnected through a resistor 90 and a capacitor 91. The input terminal 80 is connected to a capacitor 92 which is connected, on one hand, to the point common to the resistor 90 and the capacitor 91 through a diode 93 and a resistor 94 and, on the other hand, to the base of the transistor 95 through two resistors 96 and 97. The emitter of said transistor 95 is directly connected to the conductor 87 and its collector, to the point common to the resistor 90 and the capacitor 91. The base of a second transistor 98'is connected to the point common to the diode 93 and the resistor 94; its emitter is connected to the conductor 87; its collector to the point common to the resistors 96 and 97. The conductor 89 is connected to the cathode of the diode 93 through a resistor 99, the conductor 88 to the point common to the collector of the transistor 98 and the resistor 97 through a resistor 100, and the conductor 89 to the point common to the resistor 97 and the base of the transistor 95 through a resistor 101. The input terminal 81 is connected, on one hand, to the base of the transistor 95 through a diode 102 and, on the other hand, to its collector through a resistor 103. Output terminal 86 is connected to the cathode of a diode 104 whose the anode is connected to the conductor 88 through a resistor 105 and to the point common to the collector of the transistor 95 and the capacitor 91 through a capacitor 106.

The second trigger 6 has five input terminals 107, 108, 109, 110 and 111, the first three being respectively connected to the output terminals 84, 83 and 82 of the first trigger 5, the fourth, to the terminal 85 of said trigger and the fifth, to the terminal 74 of the gate 4. Said trigger has four output terminals 112, 113, 114 and 115. The input terminals 107, 108 and 109 are connected to the output terminals 113, 114 and 115 through the conductors 116, 117 and 118, respectively. The input terminal 111 is connected to a capacitor 119 that is connected, on one hand, to the conductor 117 through a resistor 120 and, on the other hand, to the base of a transistor 121 through a diode 122. The emitter of said transistor 121 is connected to the conductor 118 while its collector is connected to the conductor 117 through a resistor 123 and to the base of a transistor 124 through a resistor 125. The collector of the transistor 124 is connected to the output terminal 112 through a capacitor 126 and a diode 127 while its emitter is connected to the conductor 118. The input terminal 110, which receives the control signal issuing from the first trigger, is connected to the base of the transistor 124 through a diode 128. A resistor 129 connects the anode of the diode 128 to the collector of the transistor 124. The base of the transistor 124 is connected to the conductor 116 through a resistor 130. The point common to the capacitor 126 and the collector of the transistor 124 is connected to the conductor 117 through a resistor 131. The base of the transistor 121 is connected, on one hand, to the conductor 116 through a resistor 132 and, on the other hand, to the point common to the capacitor 126 and the collector of the transistor 124 through a resistor 133.

The output terminals 86 of the trigger 5 and 112 of the trigger 6 are connected to the selector 7. If the latter is in the position indicated in full line on the F 10. 1, only the signals issuing from the trigger 5 are emitted at its output 134; if it is in the position indicated in dotted line, the signals issuing from the two triggers appear successively at said output.

The safety circuit 9, a transistor switching circuit for the signals controlling the triggers 5 and 6 has four input terminals 135, 136, 137 and 138 and one output terminal 139. The inputs 135 and 136 are connected to the output terminals 50 and 51 of the circuit 3, while the microswitch 8 is connected between the inputs 137 and 138. A transistor 140 has its base connected to the input terminal 138 and to the input terminal 136 through a resistor 141; its collector is connected to the input terminal 135 and to the terminal 137 through a resistor 142, and its emitter, to the output terminal 139 through two capacitors 143 and 144. The two input terminals 137 and 138 are interconnected through a capacitor 145 and a resistor 146. Capacitor 147 in parallel with a resistor 148 connect the input terminal 136 to the point common to the capacitor 143 and to the emitter of the transistor 140, while a diode 149 connects the input terminal 135 to the point common to the capacitors 143 and 144.

The object of such a circuit is to establish a delay between the time at which the microswitch 8 is closed and the time at which the control signal of the trigger 5 appears at the output terminal 139. Such an arrangement prevents the trigger from being improperly controlled by accidental noise pulses and pulses created by the bounce of the microswitch.

The circuit 10 amplifying the signals supplied by the triggers 5 and 6 has three inputs 150, 151, and 152 and two outputs 153 and 154. The input terminal 150 is connected to the output terminal 134 of the selector 7, while the input terminals 151 and 152 are respectively connected to the output terminals 114 and 115 of the second trigger 6. The terminals 151 and 154 are interconnected through the conductor 155. A NPN transistor 156 has its base connected to the terminal 150 and to the conductor through a resistor 157; its collector is connected to the terminal 152, and its emitter, on one hand, to the conductor 155 through a resistor 158 and, on the other hand, to the terminal 153 through a resistor 159 and a capacitor 160.

The control circuit 12 has two input terminals 161 and 162 and three output terminals 163, 164 and 165. The terminal 162 is connected to ground and to the terminal 163. Said circuit comprises a thyristor 166 whose the control electrode is connected to the terminal 161, whose the cathode is connected to the terminal 162 and whose the anode is connected to the cathode of a diode 167, the anode of the latter being directly connected to the output terminal 164 and to the output terminal through a controlled avalanche diode 168. The output terminal 163 is connected to the output terminal 18 of the noise suppressor 1 through a shielded cable 169 whose the shield is connected ground.

The welding head 11 comprises essentially a transformer whose the primary winding 170 has one of its end terminals connected to the output terminal 164, the other end terminal being connected, on one hand, to the output terminal 165 and, on the other hand, to the output terminal 19 of the noise suppressor 1 through a shielded cable 171 and a diode 172. The welding electrodes 173 and 174 are connected to the terminals of the secondary winding 175 of the transformer whose shield 176 is connected to ground through a resistor 177 and a capacitor 178.

The welding apparatus according to the invention operates as it follows:

The closure of the microswitch 8, after a delay of a few microseconds imposed by the safety circuit 9, controls the trigger 5 that supplies a pulse having a duration approximating one one-hundredth second to the control'electrode of the thyristor 166. The latter is fired and establishes the feeding circuit of the primary winding 170 of the transformer, and, between the electrodes 173 and 174, energy sufficient for welding the extremities of two tantalum needles, without any risk of crystallization and oxidization that could be noxious to the quality of the junction is provided. As its turn, the trigger 5 controls the trigger 6 and, i the selector 7 is in the position shown in dotted line FIG. 1, a second control pulse supplied to the thyratron causes to the duration for which the primary winding 170 is fed to double as may be necessary in the case where more than two needles have to be welded. The duration of the operation being very short, it is obvious that any risk for the patient to be burned by projection of metal or excessive heating is prevented. In addition, the weld is made without any risk of electrical hazards, safety being insured:

l. by a good insulation between primary and secondary windings of the transformer whose shield is connected to ground; any risk to the patient is therefore prevented in the case of a contact of electrodes with him, 2. by the use of a noise suppressor preventing the triggers from being improperly controlled, 3. by the use of a circuit delaying the signal controlling the triggers so that a noise pulse appearing in spite of the presence of the noise suppressor cannot control the trig- 1 gers at improper times, and 4. by the protection of the thyristor against the inductive voltage surges of the primary winding of the transformer,

due to the diodes 172 and 167 avalanche diode 168.

The F IG. 2 shows a view of the welding apparatus described hereabove. The welding electrodes 173 and 174 and the microswitch 8 are grouped in a handle l79 connected to the box 180 containing the other circuit units by means of a shielded cable 181 and on which the selector 7 is apparent. It is sufficient, for welding two tantalum needles 182 and 183, implanted in the gum of a patient 184 and into contact one with the otherby their heads, to bringthe electrodes near the junction point and to push the microswitch 8 that starts the processes previously described, with the result of a very rapid production of the energy necessary for fusing the contacting heads of the needles.

It is quite understood that the description has been made by way of a nonlimitative example and that the invention may be modified within the scope of the appended claims.

I claim:

1. A surgical welding apparatus for interconnecting bone implantations comprising:

a source of welding energy;

first means connected to said source of welding energy for generating a welding control voltage in response to a predetermined input signal applied thereto;

a pair of welding electrodes;

a welding head connected between said source of welding energy and said pair of welding electrodes and being connected to said first means for supplying said pair of weldand to the controlled ing electrodes with welding energy in response to said welding control voltage generated by said first means;

second means connected to said first means and to said welding head for controlling the application of said control voltage to said welding head by said first means; and

third means for preventing the generation of said welding control voltage by said first means when said first means receives an input signal which is sufficient to trigger said first means to generate said welding control voltage but which is a signalother than said predetermined signal,

whereby said pair of electrodes will be supplied with welding energy only in response to the application of said predetermined input signal to said welding control voltage generating means, so as to ensure the safe formation of a weld interconnecting said bone implantation.

2. A surgical welding apparatus according to claim 1, wherein said welding head includes a transformer, the primary of which is coupled to said welding energy source and the secondary of which is connected to said pair of welding electrodes and wherein said second means includes a thyristor connected between the primary of said transformer and said 6 welding energy source and the control electrode of which is connected to said first means, whereby, upon the generation of a welding control voltage by said first means, said thyristor will conduct, so-that welding energy from said source will be imparted across said primary of said transformer and ultimately to said pair of welding electrodes connected across'the secondary thereof.

A surgical welding apparatus according to claim 2, wherein said first means includes a first voltage trigger circuit coupled to said source of welding energy for producing welding control voltage pulses having a first predetermined duration, which are coupled tosaid control electrode of said thyristor, whereby said pulses will control the conduction time of said thyristor so as tocontrol the time during which said welding energy is applied to said pair of welding electrodes.

4. A surgical welding apparatus according to claim 3, wherein said third means comprises a transistor switching circuit, the output of which is connected to said first voltage trigger circuit, for controlling the production of said welding control voltage pulses by said first trigger circuit.

5. A surgical welding apparatus according to claim 4, wherein said third means further includes a microswitch, and wherein said transistor switching circuit comprises a first transistor connected to said microswitch by means of a resistor-capacitor delay network having a predetermined time constant, whereby, in response to the closing of said microswitch, said transistor will supply an energizing voltage to said first trigger circuit said predetermined time after the closing of said switch, so as to ensure the proper application of welding energy to said electrodes and to prevent the application of welding energy control voltage to said welding head in response to input signals other than said predetermined signals.

6. A surgical welding apparatus according to claim 3, wherein said first means further includes a stabilized voltage generator, a control signal generator and a shaping gate connected in series between said source of energy and said first voltage trigger circuit, for properly shaping the input signal to be delivered to said first voltage trigger circuit.

7. A surgical welding apparatus according to claim 4, further including a second voltage trigger circuit and a selector switch for selectively cascading said first and second voltage trigger circuit, whereby the duration of the control voltage pulses which are coupled to the control electrode of said thyristor may be lengthened.

8. A surgical welding apparatus, according to claim 7, wherein said first and second voltage trigger circuits comprise Schmitt triggers.

9. A surgical welding apparatus according to claim- 7, further including an amplifier circuit connected between said selector switch and said thyristor.

10. A surgical welding apparatus according to claim 2, wherein said transformer further includes a shield coupled to ground and wherein said source of energy comprises a voltage source having a noise suppressor therein, so as to further reduce unwanted noise signals and prevent the undesired triggering of the generation of a welding control voltage.

I 11. A surgical welding apparatus according to claim 2, wherein said pair of welding electrodes is supported by a handle and are connected to said transformer by means of a flexible cable.

12. A surgical welding apparatus according to claim 2, further including means connected in series with said transfonner and said thyristor protecting said thyristor from inductive voltage surges produced in the primary winding of said transformer. 

1. A surgical welding appaRatus for interconnecting bone implantations comprising: a source of welding energy; first means connected to said source of welding energy for generating a welding control voltage in response to a predetermined input signal applied thereto; a pair of welding electrodes; a welding head connected between said source of welding energy and said pair of welding electrodes and being connected to said first means for supplying said pair of welding electrodes with welding energy in response to said welding control voltage generated by said first means; second means connected to said first means and to said welding head for controlling the application of said control voltage to said welding head by said first means; and third means for preventing the generation of said welding control voltage by said first means when said first means receives an input signal which is sufficient to trigger said first means to generate said welding control voltage but which is a signal other than said predetermined signal, whereby said pair of electrodes will be supplied with welding energy only in response to the application of said predetermined input signal to said welding control voltage generating means, so as to ensure the safe formation of a weld interconnecting said bone implantation.
 2. A surgical welding apparatus according to claim 1, wherein said welding head includes a transformer, the primary of which is coupled to said welding energy source and the secondary of which is connected to said pair of welding electrodes and wherein said second means includes a thyristor connected between the primary of said transformer and said welding energy source and the control electrode of which is connected to said first means, whereby, upon the generation of a welding control voltage by said first means, said thyristor will conduct, so that welding energy from said source will be imparted across said primary of said transformer and ultimately to said pair of welding electrodes connected across the secondary thereof.
 3. A surgical welding apparatus according to claim 2, wherein said first means includes a first voltage trigger circuit coupled to said source of welding energy for producing welding control voltage pulses having a first predetermined duration, which are coupled to said control electrode of said thyristor, whereby said pulses will control the conduction time of said thyristor so as to control the time during which said welding energy is applied to said pair of welding electrodes.
 4. A surgical welding apparatus according to claim 3, wherein said third means comprises a transistor switching circuit, the output of which is connected to said first voltage trigger circuit, for controlling the production of said welding control voltage pulses by said first trigger circuit.
 5. A surgical welding apparatus according to claim 4, wherein said third means further includes a microswitch, and wherein said transistor switching circuit comprises a first transistor connected to said microswitch by means of a resistor-capacitor delay network having a predetermined time constant, whereby, in response to the closing of said microswitch, said transistor will supply an energizing voltage to said first trigger circuit said predetermined time after the closing of said switch, so as to ensure the proper application of welding energy to said electrodes and to prevent the application of welding energy control voltage to said welding head in response to input signals other than said predetermined signals.
 6. A surgical welding apparatus according to claim 3, wherein said first means further includes a stabilized voltage generator, a control signal generator and a shaping gate connected in series between said source of energy and said first voltage trigger circuit, for properly shaping the input signal to be delivered to said first voltage trigger circuit.
 7. A surgical welding apparatus according to claim 4, further including a second voltage trigger circuit and a selector switch for selectively cascading said first and second voltage trigger circuit, whereby the duration of the control voltage pulses which are coupled to the control electrode of said thyristor may be lengthened.
 8. A surgical welding apparatus, according to claim 7, wherein said first and second voltage trigger circuits comprise Schmitt triggers.
 9. A surgical welding apparatus according to claim 7, further including an amplifier circuit connected between said selector switch and said thyristor.
 10. A surgical welding apparatus according to claim 2, wherein said transformer further includes a shield coupled to ground and wherein said source of energy comprises a voltage source having a noise suppressor therein, so as to further reduce unwanted noise signals and prevent the undesired triggering of the generation of a welding control voltage.
 11. A surgical welding apparatus according to claim 2, wherein said pair of welding electrodes is supported by a handle and are connected to said transformer by means of a flexible cable.
 12. A surgical welding apparatus according to claim 2, further including means connected in series with said transformer and said thyristor protecting said thyristor from inductive voltage surges produced in the primary winding of said transformer. 